Capillary Number

Written by Jerry Ratzlaff on . Posted in Dimensionless Numbers

Capillary number, abbreviated as Ca, is a dimensionless number representing the relative effect of viscous forces against the surface tension between a liquid/ gas or liquid/ liquid interface.  It is the ratio of viscous forces to surface tension forces. The equations for Capillary Number and calculation are shown below.


Capillary number calculator

Formulas that use Capillary number

\(\large{ Ca = \frac { \mu \; v }  { \sigma } }\)   


\(\large{ Ca }\) = Capillary number

\(\large{ \mu }\)  (Greek symbol mu) = dynamic viscosity

\(\large{ \sigma }\)  (Greek symbol sigma) = shear tension

\(\large{ v }\) = velocity of fluid



Tags: Equations for Fluid Calculators